In aeronautics, the relative wind is the direction of movement of the atmosphere relative to an aircraft or an airfoil. It is opposite to the direction of movement of the aircraft or airfoil relative to the atmosphere. Close to any point on the surface of an aircraft or airfoil, the air is moving parallel to the surface; but at a great distance from the aircraft or airfoil the movement of the air can be represented by a single vector. This vector is the relative wind or the free stream velocity vector.
The angle between the chord line of an airfoil and the relative wind defines the angle of attack. The relative wind is of great importance to pilots because exceeding the critical angle of attack will result in a stall, regardless of airspeed.
Read more about Relative Wind: Relative Wind in Freefall
Famous quotes containing the words relative and/or wind:
“And since the average lifetime—the relative longevity—is far greater for memories of poetic sensations than for those of heartbreaks, since the very long time that the grief I felt then because of Gilbert, it has been outlived by the pleasure I feel, whenever I wish to read, as in a sort of sundial, the minutes between twelve fifteen and one o’clock, in the month of May, upon remembering myself chatting ... with Madame Swann under the reflection of a cradle of wisteria.”
—Marcel Proust (1871–1922)
“To be shelterless and alone in the open country, hearing the wind moan and watching for day through the whole long weary night; to listen to the falling rain, and crouch for warmth beneath the lee of some old barn or rick, or in the hollow of a tree; are dismal things—but not so dismal as the wandering up and down where shelter is, and beds and sleepers are by thousands; a houseless rejected creature.”
—Charles Dickens (1812–1870)